During postnatal development, a newborn's intestine experiences a process of maturation that ends with the production of gastrointestinal epithelium that functions as a selective barrier (i.e., gut barrier). The gastrointestinal epithelium permits the absorption of nutrients, electrolytes and water, while preventing exposure to dietary and microbial antigens, including food allergens. Specifically, this barrier limits the passage of antigens to the systemic circulation, thereby preventing infection, inflammatory reactions, and other gastrointestinal diseases and disorders that may occur during infancy and later in life. For very young infants, and particularly, preterm infants, who have an immature immune system and intestinal tract, development of suboptimal intestinal flora may result in infection, diarrhea, allergies, and food intolerance.
Barrier formation and maintenance has been found to be affected by the diet. Breast milk contains components that not only act as pathogen receptor analogues, but also activate immune factors by infant intestinal epithelial cells and/or associated immune cell populations to enhance development and maturation of the infant's gastrointestinal and immune systems.
Not all infants, however, are in a position to receive human breast milk. It would therefore be desirable to provide nutritional compositions, and synthetic infant formulas in particular, that can produce nutritional benefits including improved gastrointestinal growth, development, and maturation. It would additionally be beneficial if the nutritional compositions could enhance immunity against microbial infections and other gastrointestinal diseases, conditions, and disorders.